You Learned Rails...Now What?

If you have been using Rails for 6 months or more but you still feel like you could be doing a lot better...

...and if you are not really happy with your code...

...then this could be the most important message you will ever read.


my name is Jesus Castello & I have been using Ruby for over 6 years & teaching it for about 2 years.

In my experience, most of my students have this uneasy feeling because they haven't been taught Ruby fully.

Most courses & books just focus on the surface details.

That's a bit of a problem when it comes to writing better Ruby code & being able to do projects outside of Rails.

That's why I invested over 100 hours of my time to put together a resource for you...

A resource which:

  • Helps you build a solid foundation of Ruby skills
  • Bridges the gap between the fundamentals & more advanced concepts
  • Shows you the tools, ideas and examples you need to understand things better

The resource I'm talking about is Ruby Deep Dive, the book for serious Ruby developers.

It's Not Only a Book, It's a Complete Package

Ruby Deep Dive is a complete package to help you build a solid Ruby foundation, bridging the gap between the fundamentals & more advanced concepts.

This is what is included:

  • A 160-page PDF eBook
  • 100+ Code Examples You Can Copy & Paste For Quick Learning
  • 8 Printable Quick-Reference Mindmaps
  • A List of Resources to Help You Keep Growing As a Developer
  • Answers to All Your Ruby Questions Via Email

Mary Katherine



“I've been reading Ruby Deep Dive as I have time and finding it to be SUPER​​​​ helpful​​​​​.

It's exactly the 'next step' I needed after doing all the beginner tutorials. Thanks for writing it!!! :)“

Some of the things you will discover inside Ruby Deep Dive:

  •  The secrets behind blocks, procs & lambdas!
  •  Why Ruby objects don't have methods, only classes do
  •  How to make your Ruby programs faster
  •  Why Enumerable is the most important Ruby class & how to get the most out of it!
  •  The dangers of class variables & why you should avoid them like the plague
  •  A review of the core Ruby classes so you aren't missing out on something important!
  •  ...and a few other things that you will not find on your average Ruby book

Imagine being able to understand every line of code in your project...

...and learning to use the full power of Ruby so you can write better programs that you can be proud of.

Ruby Deep Dive will help you do that.

Click the yellow button below & grab your copy today :)


(You will instantly receive a download link to a zip file containing the PDF of the book plus all the learning resources.)


If you don't love the book & all the included bonus content (cheatsheets, guides, support), just let me know & I will give your money back.

Table of Contents

  1. Using Pry to Learn Ruby
    • The Power of Pry
    • Where did this method come from?
    • Debugging using Pry
  2. Understanding Exceptions
    • What are Exceptions and Why They Happen
    • Understanding Stack Traces
    • Using Exceptions
    • At Exit
    • Custom Exceptions
    • Common Errors Guide
  3. Working with Data
    • Strings
      • Putting Strings Together
      • Manipulating Strings
      • Working with Characters
      • Immutability and Frozen Strings
    • Arrays
      • Let's review: What's an Array?
      • Basic Operations
      • Iterating Over Arrays
      • More Array Operations
      • The Splat Operator
      • Operations Involving Multiple Arrays
    • Hash tables
      • Using Hash Tables
      • Basic Usage
      • Iterating Over Hash Values
      • Default Values
      • Using Fetch and Merge
      • The Dig Method (new in Ruby 2.3)
    • Ranges
      • Inclusive & Exclusive ranges
      • Iterating over ranges
      • Stepping
      • Random number within a range
    • Data Serialization
      • CSV
      • JSON
      • YAML
  4. The Ruby Object Model
    • Introduction to the object model
    • Super-classes
    • The singleton class
    • Ruby Internals
    • Constants in Ruby
    • Constant Lookup
    • Ruby Method Sugar
  5. Procs & Lambdas
    • What's a block & how to use them
    • Lambdas vs Blocks
    • Closures
    • Using to_proc
  6. Understanding Require
    • Why do we need require
    • How Ruby gems are required
    • Require vs Require Relative vs Load
  7. Regular Expressions
    • Character ranges
    • Capture groups
    • LookAhead & LookBehind
    • Ruby methods for working with regular expressions
  8. Modules
    • What is a module & how it's different from a class
    • 5 different ways to use modules
  9. Enumerable
    • 3 Ruby methods everyone should know
    • How to include Enumerable in your own class
    • What are Lazy Enumerators & when to use them
  10. Using Sinatra
    • Sinatra fundamentals
    • How to write a simple API
    • Interacting with a database
  11. Performance
    • Benchmarking vs Profiling
    • How to make your programs faster
  12. Comparing Objects
    • The Comparable module
    • The spaceship operator
  13. Metaprogramming
    • What is self?
    • How do you handle undefined methods?
    • Creating dynamic methods
    • Creating dynamic constants
    • Using hooks
  14. Writing a DSL
    • What is a DSL & how to implement one

 Jay Wilburn​​​​ 

Full-Stack Developer 


"This book has helped me understand things better. And I have been able to apply those learnings into some of my work."